Flow control valve

ABSTRACT

A structure is provided for use in a globe valve or the like in installations where constant flow is desired despite variations in inlet and outlet pressures. The valve stem is attached to the structure and movement of the stem determines the effective maximum flow through the valve. Inlet and outlet pressures operate upon opposite sides of a diaphragm, and the differential in pressure causes movement of a valve member relative to an orifice and thereby maintains constant flow through said orifice.

United States Patent Martin 1 [s41 FLOW CONTROL vALvE- [72] Inventor:Thomas B. Martin, Micro-Pump Corporation, 1021 Shary Court, Danville,Calif. 945 18 22 Filed: on. s, 1910 [21] Appl. No.: 79,085

[52] us. ci. Wm/s01, 99/307 [51] Int. Cl. l6lt3l/36 [58] Field ofSeai-ch..137/495,501,6l4.l7;99/282,

[56] References Cited UNITED STATES PATENTS 2,623,331 12/1952 Greening..l37/50l 151' 3,677,288 [451 July'l8, 1972 Primary Examiner-Henry "r.Klinksiek Attorney-Julian Caplan s7 Answer.

A structure is provided for use in a globe valve or the like ininstallations where constant flow is desired despite variations in inletand outlet pressures. The valve stem is attached to the structure andmovement of the stem determines the effective maximum flow through thevalve. lnlet and outlet pressures operate upon opposite sides of adiaphragm, and the differential in pressure causes movement of a valvemember relative to an orifice and thereby maintains constant flowthrough said orifice.

9 Claims, 5 Drawing I PATENTEDJUH 81912 3.677288 SHEET 1 0r 2 26 2732FIG. 1

FIGQ.

, INVENTOR.

THOMAS B. MARTIN PATENTEUJUL'I 81912 3.677.288

SHEET 2 [1F 2 I NVEN'TOR.

4 THOMAS B. MARTIN ATTORNEY FLOW CONTROL VALVE This invention relates toa new and improved flow control valve which, in an ordinary globe valvebody or the like combines a metering orifice which is set by the valvehandle and also a control orifice which maintains constant flow throughthe valve, once it has been set by the valve handle, despite variationsin inlet pressure and/or outlet pressure. Reference is made to US Pat.No. 3,357,448 on which the present invention is an improvement.

Ordinary globe valves are constructed so that by adjustment of theposition of the valve stem, the effective opening of the orifice is setand such setting is ordinarily effective only if the pressuredifi'erential between the inlet and the outlet of the valve remainsconstant. The present invention provides a means for maintainingconstant flow despite variations in the differential of pressure betweenthe inlet and the outlet of the valve.

The valve body is substantially the same in dimensions and appearance asconventional globe valve bodies and hence may be interchanged therewithin standard piping systems. Further, the operating control handle issubstantially the same as in conventional valves.

A principal feature and advantage of the invention is the fact that thevalve may be installed where the pressure at the inlet or the backpressure at the outlet, or both, are variable. The valve compensates forsuch pressure variations so that the volume of flow through the valveremains constant. From time to time, as required, such volume may beadjusted by movement of the valve stem.

One of the features of the invention is the simplicity of theconstruction and the facility with which it may be manufactured.

Still another feature of the invention is the fact that the valveoperating structure may be installed and removed through the valvebonnet and the regulating structure may be replaced with great case.

A feature of a modification of the invention is the use of a balancingpiston which enhances the accuracy of the metering valve and moreeffectively dampens fluctuations in the movement of the valve structurewhere there are rapid changes'i inlet or outlet pressure.

Other objects of the present invention will become apparent upon readingthe following specification and referring to the accompanying drawingsin which similar characters of reference represent corresponding partsin each of the several views. r

In the drawings:

FIG. 1 is a vertical sectional view through a valve formed in accordancewith the present invention.

FIG. 2 is an enlarged sectional view of a portion of FIG. 1 showing onthe left hand side the valve closed and on the right hand side the valveopened.

FIG. 3 is a fragmentary sectional view taken substantially along theline 3-3 of FIG. I.

FIG. 4 is a fragmentary sectional view similar to FIG. 1 of amodification.

FIG. 5 is a fragmentary sectional view of a further modified valueconstruction having a balancing piston.

The present invention employs a valve housing 11 which is similar tothat of conventional globe valves. Housing 11 has an inlet port 12 andan outlet port 13. It will be understood that the pressure at ports 12and 13 is subject to variation. Housing 11 is formed with an upwardextension 14 and partially within extension 14 is a valve body 16supported from the bottom of the housing 11 by a support partition 17which divides the housing 11 into an inlet compartment 19 and an outletcompartment 20. The cylindrical interior of body 16 communicates withinlet compartment 19 through an inlet orifice 18, the body 16surrounding orifice 16 comprising a valve seat 24.

Supported above extension 14 is a bonnet 21 having adjacent its bottomedge a flange 22 secured to the threaded exterior of extension 14 by anannular nut 23. Within bonnet .21 is a valve stem 26 having a threadedmiddle portion 27 which turns in a threaded bore in bonnet 21 when thehandle 28 of hereinafter explained. Such structure 36 may consist of anupper portion 37 which is hollow and the bottom of the hollow is closedoff by a disc-like lower portion 38 held in place by the inward turnededge 39 of upper portion 37. A ring seal 4] seals the exterior of valvestructure 36 to the cylindrical cavity of valve body 16. One means tosecure the structure 36 to stem 37 is to form in top 42 of upper portion37 a radial slot 43 which is undercut in a wider slot 44 (see FIG. 3).To assemble structure 36 on stem 26, the bottom button 32 is movedradially inward in wider slot portion 44 and the narrow portion 31through the slot 43. Thus, the two parts are fitted together forvertical movement and cannot be separated without removing the structure36 from the interior of the housing I l and then sliding them apart.

As is apparent from FIG. 1, one of the features of the invention is thefact that the 'valve structure 36 may be withdrawn through theopening inupward extension 14 by removing nut 23 and bonnet 21, and drawing thestem 26 upward.

In the form of the invention shown in FIGS. 1 and 2, there is an annularseal 46 which may be in the shape of a truncated triangle incross-section which is inserted in a complementary groove in the bottomof lower portion 38 and which surrounds orifice 18. As structure 36moves toward and away from seat 24, the volume of flow through orifice18 is metered.

An opening 47 in the bottom of lower portion 38 inside the confines ofseal 46 communicates with one side of a diaphragm 48 disposed insidestructure 36. Diaphragm 48 has a peripheral rim 49 which fits under aninternal bead $1 on upper portion 37. In assembling structure 36, priorto inward turning of edge 39, rim 49 is installed below bead 51 andlower portion 38 is then forced against the rim 49. Thereupon, thebottom edge 39 is turned inward locking the diaphragm in place.Diaphragm 48 divides the interior of valve structure 36 into an inletpressure chamber 52 which communicates with the inlet compartment 19through opening 47 and orifice l8 and an outlet pressure chamber 53which communicates with housing 16 through openings 54 in the wall ofupper portion 37. As shown in FIG. 2, below sea] 41 structure 36 issmaller than the interior of body 16, and hence'fluid entering withinbody 16 flows around the outside of structure 36, then thrOugh openings54 into chamber 53. Fixed to the upper surface of diaphragm 48 is afitting 56 which has a conical tip 57. Within structure 36 is an orificeplate 58 formed with a central orifice 59 which cooperates with tip 57to control flow. Plate 58 is fixed against upward movement by shoulder61 on the interior of top portion 37 and interposed between plate 58 andfitting 56 is a coil spring 62 which biases the fitting downward to theleft hand position of FIG. 2. Above plate 58 and also above seal 41 areopenings 63 through which the fluid passing through the orifice 59 isdischarged into the outlet compartment 20.

In the operation of the valve of FIGS. 1-3, the handle 28 is turneduntil the relationship of seal 46 and orifice 18 meters the flow desiredthrough the valve.

A variable pressure may be applied to inlet port 12 and a variable backpressure may be applied to outlet 13. The flow through the valve isrestricted from compartment 19 through openings 54 into chamber 53 onthe inlet side of orifice plate 58 depending on the position of seal 46.A pressure drop is caused by the first restriction in flow, which dropincreases when the flow increases and decreases when the flow decreases.The dropresults in higher pressure on the inlet side of diaphragm 48 anda corresponding lower pressure on the opposite side thereof. When thepressure diflerential overcomes the force of spring 62, the meteringvalve begins to function and tip 57 moves into orifice 59 to introduce'a second restriction offlow. The second or variable restriction isvaried by the force of spring 62 to maintain a constant pressure dropacross the first or fixed restriction. Therefore, flow through the fixedrestriction and correspondingly flow through the valve is substantiallyconstant. Any variations in supply pressure or back pressure are metautomatically by compensating changes in pressure drop in the secondrestriction. Choice of preload of spring 62 determines the magnitude ofpressure drop which must exist before the valve parts move.

A modification of the invention is shown in FIG. 4. How ever, becausemany of the parts of FIG. 4 are identical or very similar to those ofFIGS. 1-3, the same reference numerals followed by subscript" a are usedto designate corresponding parts. In this form of the invention, theseal 46 of FIGS. 1 and 2 is eliminated. Instead, the lower portion 38ais formed with a downward extending tip 66 which cooperates with orifice18a to perform the metering function of the valve. The flow controlfunctions are essentially the same in the modification of FIG. 4 as inFIGS. 1-3.

FIG. 5 shows a still further modification of the structure, and becausemany of the parts are similar to those of FIGS. 1-3, the same referencenumerals followed by the subscript b are used to designate correspondingparts. In this form of the invention, fitting 56b is formed with anupward'extending stem 71 which passes through orifice 59b. On the upperend of stem 71 is a piston, 72 which fits within a cylinder 73 formed inthe underside of top 42b. The upper end of cylinder 73 is maintained atthe same pressure as outlet pressure chamber 53b by means of alongitudinal duct 74 extending downward from the upper end of piston 72which connects to transverse ducts 76. A filter 77, which may be made ofceramic, sintered metal, felt or other suitable material, and which isheld in place by a filter retainer 78 surrounds ducts 76 and preventsthe ducts and the cylinder 73 from being clogged by dirt or otherforeign matter. It will be seen that in the form of the invention shownin FIG. 5 there is a dampening function. Thus, fluctuations in thepressure do not cause a rapid hunting movement of diaphragm 48b byreasonof the use of the balancing piston 72. The control orifice 56b iseffectively engaged, by the exterior shoulder 79 of stem 71. The area ofthe balance piston 72 matches the area of the control orifice 59b, andthereby eliminates the effect of the area of control orifice 59b.

What is claimed is: I 5

l. A valve of the character described comprising a housing, a'firstpartition dividing the interior of said housing into inlet and outletcompartments, said first partition forming a cylindrical valve bodyhaving an end wall formed with a first orifice opening into said inletcompartment, a movable valve stem, means external of said housing formoving said valve stem toward and away from said first orifice, a hollowvalve structure reciprocal within said valve body having an externalfirst seal ring between said valve structure and said valve body and afirst valve element in proximity to said first orifice, means connectingsaid stem to said valve structure to position said first valve elementin relation to said first orifice, a movable second partition withinsaid valve structure, having a second seal ring between said secondpartition and the interior of said valve structure dividing the interiorof said valve structure into first and second chambers, a first passagefor fluid communication between-said first chamber and said inletcompartment through said first orifice, a second passage for fluidcommunication between said first' orifice and-said second chamber, a

second orifice for fluid communication between said second chamber andsaid outlet compartment, whereby fluid flow from said first orificepasses through said second passage, then inside said second chamber,then out said second orifice and into said outlet compartment, a secondvalve element movable with said second partition and cooperable withsaid second orifice to adjust the pressure drop across said secondorifice, and resilient means biasing said second valve element away fromsaid second orifice, whereb the lpressure of fluid flowing in saidsecond chamber will be ess t an the pressure in s second chamber will beless than the pressure in said first chamber by an amount which islimited by the deflection of said spring.

2. A valve according to claim 1 in which part of said valve structure isdimensioned smaller than the interior of said cylindrical valve body,said valve structure formed with at least one opening leading into saidsecond chamber and located on the side of said first seal ring towardsaid end wall, whereby fluid flow from said first orifice passes insidesaid valve body around the outside of said valve structure, then insidesaid second chamber, then out said second orifice and into said outletcompartment.

3. A valve according to claim I in which said movable second partitionis in the form of a diaphragm.

4. A valve according to claim 3 in which said valve structure isformedwith a hollow first portion formed with an internal first shoulder, andan internal second shoulder, an orifice plate defining said secondorifice ,received against said first shoulder, said spring forcing saidorifice plate against said first shoulder, said second valve membercooperating with the opposite end of said spring to bias said diaphragmaway from said second orifice, a second valve structure portion securingthe periphery of said diaphragm, means for holding said first and secondportions of said valve structure in assembled position,

said first passage consisting of an opening in said second portion.

5. A valve according to claim 11 in which said end wall is formed withan internal seat and in which said first valve element comprises anannular seal ring surrounding said, first orifice and cooperable withsaid seat to meter fluid flow through said valve.

6. A valve according to claim 1 in which said first valve elementconsists of a tapering tip cooperable with said first orifice to meterfluid flow through said valve, said first passage comprising a centralduct in said tip.

7. A valve according to claim I in which said valve structure is formedwith an internal cylinder on the upstream side of said second orifice inalignment with said second orifice, said second valve element beingformed with a shoulder portion cooperable with said second orifice toadjust the pressure drop across said second orifice, said second valveelement also having a piston portion reciprocable within said cylinderand formed with ducts to establish fluid communication between theinside of said cylinder and said second chamber.

8. A valve according to claim 7 which further comprises a filterenclosing said ducts to prevent ingress of foreign matter into saidducts and said cylinder.

9. A valve according to claim 1 in which said movable valve stem isformed with a constructed thickness spaced slightly outward from itsinner end, said valve structure having a flange formed with a slotextending from the periphery of said flange, said constricted thicknessreceived within said slot with wider portions of said stem both aboveand below said flange for mechanically connecting said stem to saidvalve structure.

i 10K I 18 IF

1. A valve of the character described comprising a housing, a firstpartitiOn dividing the interior of said housing into inlet and outletcompartments, said first partition forming a cylindrical valve bodyhaving an end wall formed with a first orifice opening into said inletcompartment, a movable valve stem, means external of said housing formoving said valve stem toward and away from said first orifice, a hollowvalve structure reciprocal within said valve body having an externalfirst seal ring between said valve structure and said valve body and afirst valve element in proximity to said first orifice, means connectingsaid stem to said valve structure to position said first valve elementin relation to said first orifice, a movable second partition withinsaid valve structure, having a second seal ring between said secondpartition and the interior of said valve structure dividing the interiorof said valve structure into first and second chambers, a first passagefor fluid communication between said first chamber and said inletcompartment through said first orifice, a second passage for fluidcommunication between said first orifice and said second chamber, asecond orifice for fluid communication between said second chamber andsaid outlet compartment, whereby fluid flow from said first orificepasses through said second passage, then inside said second chamber,then out said second orifice and into said outlet compartment, a secondvalve element movable with said second partition and cooperable withsaid second orifice to adjust the pressure drop across said secondorifice, and resilient means biasing said second valve element away fromsaid second orifice, whereby the pressure of fluid flowing in saidsecond chamber will be less than the pressure in said second chamberwill be less than the pressure in said first chamber by an amount whichis limited by the deflection of said spring.
 2. A valve according toclaim 1 in which part of said valve structure is dimensioned smallerthan the interior of said cylindrical valve body, said valve structureformed with at least one opening leading into said second chamber andlocated on the side of said first seal ring toward said end wall,whereby fluid flow from said first orifice passes inside said valve bodyaround the outside of said valve structure, then inside said secondchamber, then out said second orifice and into said outlet compartment.3. A valve according to claim 1 in which said movable second partitionis in the form of a diaphragm.
 4. A valve according to claim 3 in whichsaid valve structure is formed with a hollow first portion formed withan internal first shoulder, and an internal second shoulder, an orificeplate defining said second orifice received against said first shoulder,said spring forcing said orifice plate against said first shoulder, saidsecond valve member cooperating with the opposite end of said spring tobias said diaphragm away from said second orifice, a second valvestructure portion securing the periphery of said diaphragm, means forholding said first and second portions of said valve structure inassembled position, said first passage consisting of an opening in saidsecond portion.
 5. A valve according to claim 11 in which said end wallis formed with an internal seat and in which said first valve elementcomprises an annular seal ring surrounding said first orifice andcooperable with said seat to meter fluid flow through said valve.
 6. Avalve according to claim 1 in which said first valve element consists ofa tapering tip cooperable with said first orifice to meter fluid flowthrough said valve, said first passage comprising a central duct in saidtip.
 7. A valve according to claim 1 in which said valve structure isformed with an internal cylinder on the upstream side of said secondorifice in alignment with said second orifice, said second valve elementbeing formed with a shoulder portion cooperable with said second orificeto adjust the pressure drop across said second orifice, said secondvalve element also having a piston portion Reciprocable within saidcylinder and formed with ducts to establish fluid communication betweenthe inside of said cylinder and said second chamber.
 8. A valveaccording to claim 7 which further comprises a filter enclosing saidducts to prevent ingress of foreign matter into said ducts and saidcylinder.
 9. A valve according to claim 1 in which said movable valvestem is formed with a constructed thickness spaced slightly outward fromits inner end, said valve structure having a flange formed with a slotextending from the periphery of said flange, said constricted thicknessreceived within said slot with wider portions of said stem both aboveand below said flange for mechanically connecting said stem to saidvalve structure.